In the related art, as disclosed in PTL 1, a hybrid driving system is known in which one engine, one transmission, and one motor/generator are combined, a drive shaft and a driven shaft of the transmission are connected to each other by an eccentric body driving device provided in the drive shaft and a one-way clutch provided in the driven shaft, output of an engine is introduced to the drive shaft of the transmission, the motor/generator can be selectively connected to the input side of the transmission or the output side of the one-way clutch via the clutch means, or can be simultaneously connected to both the input side of the transmission and the output side of the one-way clutch.
In the driving system, an engine running which uses only the driving force of the engine, an EV running which uses only the driving force of the motor/generator, and a parallel running which uses both the driving force of the engine and the driving force of the motor/generator can be performed. Moreover, regenerative energy can be obtained using a regenerative operation of the motor/generator, and simultaneously, regenerative braking can be used in a driving wheel. The motor/generator can also start the engine.